A novel antibody from rheumatoid arthritis patients

A 106 base-pair length DNA sequence was isolated from rheumatoid synovium. Base sequence analysis showed this fragment to correspond to sequences already reported as the non-transcribed spacer of ribosomal DNA. Base sequence analysis also revealed that a fused protein has a unique five amino acid sequence. This five amino acid sequence was considered to be an epitope for an antibody. This antibody was named BUNGO antibody (BUNGO is the old name for Oita prefecture). An antigen peptide was synthesized chemically in accordance with the amino acid sequence of the epitope. Using this synthetic peptide, BUNGO antibody in serum was measured. Twelve of 32 patients (37.5%) with RA (rheumatoid arthritis) tested positive for the antibody. Five of 32 (15.6%) age and sex-matched control subjects were positive, indicating a significant difference from the RA group (chi 2 = 3.9, p < 0.05).